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G. CATANZANO. METHOD OF MOUNTING PROPELLERS UPON SHIPS.

' APPLICATION man JAN. 11. 1919 1,317,861. 7 Patented 0ct. 7,1919.

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G. CATANZANO.

APPLICATION -FlLED 1AN.H| 1919.

Patented Oct. 7, 1919.

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(eroZamo Uai'vanzano,

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GnnoLAMo CATANZANO, or anemia, tiles-renewin METHOD or Momma snotntents nro'iv sans:

Specification of Letters Iaten t.

ratentea est. 7, 1919.

Application filed January 17, 1919. Serial No. 271,684.

Toallwhom it may concern:

Be it known that I, GERoLAMo CATAnzANo,

' a citizen of the United States, and resident of Somerville, county of Middlesex, and ommonwealth of Massachusetts, have invented an Improvement in Methods of Mounting Propellers Upon Ships, of which the following description, in connection with the accompanying drawings, is a specification, like characters on the drawings repre senting like parts.

The invention relates to an improvement in the method of installation of the propeller upon the hull of a vessel, that is forward of the stern, and in .such a manner as to obviate practically all the difficulty usually encountered in vessels of ordinary construction, namely, the raising of the propeller out of the water by the rolling and pitching of the vessel. V

eferring to the drawings illustrating one embodiment of my invention described herein f Figure 1 is a side view of the stern of a vessel equipped with its propeller according to my novel method;

Fig. 2 a longitudincl 2-2 of F section on the line ig. 1 looking up; i g. 3 a cross-section on the line 3-3 Fig. 1 looking toward the right;

Fig. 4 a bottom view of a hull of a vessel provided with three propellers according to my novel method; o

Fig. 5 a cross-sectional view of a hull with three propellers, on the line 55 Fig. l;

ig. 6 a cross-section of a vessels hull equipped with two propellers in a manner similar to Fig 4;.

In Figs. 1, 2 and 3 I have shown one method of mounting or installing a propeller wherein the hull 12 is provided with a transverse housing or passage-way 13 completely across the narrow lower part of the hull, which housing is, of course water tight, although the top of the housing may be provided with plates suitably secured in position so that by removal thereof, access may 'behad to the propeller for the installation, removal or repair of the same. 1

By housing the propeller as described at a substantial distance from the stern of the vessel, it is placed so far forward that no pitching of the vessel will bring the propeller out of water to any substantial degree. As is normally just below blades the water line which is identified with the i section line 3+3.

This feature was suggested in my issued Patent No. 636, 1 88, but it has been found that while the installation of the propeller as described prevented the pitching of the vessel the rear wall 14 of the housing by trapping the water itself acted as a drag upon the movement of. the vessel, or the body of water in the housing was sufficient topresent an appreciable, drag against the forward movement of the vessel. The farther the propeller is advanced on the hull, the longer the passage across the hull necessarily is, and the longer the extent of wall to thus act as a drag. To obviate this objection I have conceived the novel idea Figs. 1, 2 of providing a passage 15 from said propeller housing rea'rwardly, leading out at one side of the vessel, thus permitting the water trapped in the housing to flow rearwardly and escape, thereby eliminating almost all the drag above referred to.

nd again unless the propeller is located 'below the water line it will race when the are raised out'of the water by the rolling of the hull, just as it races when the blades are raised from the water by the for- 'ward and downward pitching of the hull. :Accordingly I have located the propeller entirely below the water line, thus eliminating all danger of racing from the rolling of the vessel. 1

In the construction in Fig. 6 where two propellers are used, the positions of the propeller-s being relatively near the outer wall of the hull, permits cutting away or overhang ing of a portion 16 of the hull forming housings adjacent each propeller to provide ready means of egress for the water which would otherwise be trapped therein. I have also found that by-installing or housing the propeller in a depressed, substantially cigarshaped section of the 111111, the propeller may be advanced materially away from the stern with great advantage as in the case of the construction shown in Figs. 1 and 2, and all danger of trapping the water avoided, while substantially all the advantage of the c011- struction shown in Figs. 1 and 2 is maintained. This may be satisfactorily accomplished by, see Fig. 4, providing the hull with the depressed overhanging areas 16.

These depressed or concave areas should be as nearly open as possible and still obtain the desired amount of depression necessary to raise the propeller sufficiently, and avoid its being located too low down, and thus in effect increase the draft of the vessel. I have found that if the depression is constructed to have a flaring mouth, Fig. 5, best results are obtained, as it avoids all tendency to confine the water in a more or less inclosed channel or raceway.

Where the water is thus confined, the result of the pressure of the propeller blades against it is not. the same as in the case where the water is substantially unconfined; and the propeller does not, under these conditions, impart to the vessel the same degree of forward impetus which is usually imparted under normal conditions. There is a certain amount of lateral displacement of the water owing to the action of the propeller blades upon it under normal conditions, and this lateral displacement of the Water is not permitted when the water is confined in a channel, the walls of which are too close together so as to form substantially a raceway or conduit.

These walls seem to prevent lateral motion of the Water under the impact of the propeller blade, with the result that there is a loss of power in the action of the propeller. Apparently there should be suiiicient room for tree circulation of the water in all directions around the propeller following the constantly changing direction of pressure of the propeller blade upon the water owing to the inclined surface of the blade, and the angle at which it contacts with the water as it rotates, and this free circulation of water is not obtained in a relatively closed channel or conduit.

Accordingly also for the reasons stated, the depression must not be too deep, and I Copies of this patent may be obtained for five cents each, by addressing the providing a free passage the houslng under the lnfluence of the prohave found depressions substantially as shown in Figs. l and 5 to produce best results. In the construction shown in Fig. 5 Where three propellers are used the channel 15 is not shown provided for the escape of the water near the center 01": the housing as in Figs. 1 and 2, the space in the rear of the propeller being open. except for the overhanging section 16, the housing near the outer propellers however, being cut away as in Fig. i, to permit ready egress of the water therefrom. l

Obviously with a propeller located as in Figs. 1 and 5 it is practically an impossibility for the boat to roll or pitch sufliciently to raise the propeller out of the water to any substantial degree.

Claims: 7

1. A ships hull having a propeller housing relatively advanced from the stern and substantially below the Water line, and a trapped water releasing passage leading from the housing rearwardly at or above the water line to provide a free passage for the water from the housing under the influence of the propeller.

2. The combination with a propeller of a I ships hull having a transverse propeller housing relatively advanced from the stern and substantially all below the water line to prevent racing of the propeller during the rolling of the hull, and having a trapped water releasing passage extendedtherefrom rearwardly at or above the water line, and for the water from peller.

In testimony whereof I have signed my name to this specification.

GEROLAMO GATANZANO.

Commissioner of Patents,

Washington, D. G. 

